The present invention relates to an ultraviolet/infared absorbent glass having a greenish color shade. Particularly, it relates to an ultraviolet/infared absorbent glass which has a high visible light transmittance and light greenish color shade so that it is useful for a window of a vehicle and a building.
Recently, a variety of glasses having an ultraviolet/infrared absorptivity and a greenish color shade to be used as a vehicle windshield has been proposed with the view of preventing degradation of luxurious interior materials and reducing cooling load of the vehicle.
For example, an ultraviolet/infrared absorbent glass having a greenish color shade disclosed in Japanese Patent H6-88812B consists of soda-lime glass including colorants consisting of 0.65 to 1.25 wt. % total iron oxide expressed as Fe2O3, 0.2 to 1.4 wt. % CeO2 or 0.1 to 1.36 wt. % CeO2 and 0.02 to 0.85 wt. % TiO2.
An ultraviolet/infrared absorbent glass having a relatively light greenish color shade disclosed in Japanese Patent H5-78147A consists of a base glass consisting of 68 to 72 wt. % SiO2,1.6 to 3.0 wt. % Al2O3, 8.5 to 11.0 wt. % CaO, 2.0 to 4.2 wt. % MgO, 12.0 to 16.0 wt. % Na2O and 0.5 to 3.0 wt. % K2O and colorants comprising 0.58 to 0.65 wt. % total iron oxide expressed as Fe2O3, 0.1 to 0.5 wt. % CeO2 and 0.1 to 0.4 wt. % TiO2.
An ultraviolet/infrared absorbent glass disclosed in Japanese Patent H8-208266A and Japanese Patent H9-208254A has a relatively high visible light transmittance and a greenish color shade having high see-through visibility.
An ultraviolet/infrared absorbent glass disclosed in Japanese Patent H8-208266A consists of soda-lime-silica glass including colorants comprising 0.52 to 0.63 wt. % total iron oxide expressed as Fe2O3, 0.9 to 2 wt. % total CeO2 and 0.2 to 0.6 wt. % TiO2 wherein the divalent iron oxide expressed as Fe2O3 is 28 to 38 wt. % of the total iron oxide expressed as Fe2O3.
An ultraviolet/infrared absorbent glass disclosed in the Japanese Patent H9-208254A consists of a base glass comprising 67 to 75 wt. % SiO2, 0.05 to 3.0 wt. % Al2O3, 7.0 to 11.0 wt. % CaO, 2.0 to 4.2 wt. % MgO, 12.0 to 16.0 wt. % Na2O, 0.5 to 3.0 wt. % K2O, 0.05 to 0.30 wt. % SO3 and 0 to 1 wt. % SnO2 and colorants comprising 0.40 to 0.90 wt. % the total iron oxide expressed as Fe2O3, 1.0 to 2.5 wt. % CeO2, 0.1 to 1.0 wt. % TiO2, 0.0010 to 0.040 wt. % MnO, 0.0001 to 0.0009 wt. % CoO and 0.0001 to 0.0010 wt. % Cr2O3.
The colored film-coated glass can be prepared in an ion exchanging process in which ultra fine particles of an inorganic salt including silver or copper transmit into the glass base due to baking the glass applied with the inorganic salt including the silver or the copper on a surface thereof to cause transparent colloidal development, in a metallic film forming process in which a metallic film is flashed onto a glass base due to sputtering, or in a film forming process in which a film of metallic ultrafine particles is formed due to heating a glass base applied with the metallic salt compound dissolved in a solution of metal alcoxide.
Color development due to surface plasmon of metallic ultrafine particles is superior in heat resistance and light resistance and has been used in coloring of glass or earthenware. For example, according to J. Sol-Gel. Sci. Techn. 1,305-312 (1994), a colored film is obtained due to forming fine particles of gold by heating a glass base applied with a solution of alcoxide including chloroaurate and silane.
The aforementioned conventional ultraviolet/infrared absorbent glasses generally have problems as followings.
An ordinary ultraviolet/infrared absorbent glass having a greenish color shade including the glass disclosed in the Japanese Patent H6-88812B is possibly improved in the ultraviolet and infrared absorptivity so far as the visible light transmittance is within a permissive range (for example, more than 70% when the glass is employed for a front windshield of a vehicle.) and has a relatively deep greenish color shade having an excitation purity in a range of 2.4 to 3.3%. However, a glass having a light greenish color shade is sometimes preferred for a window of a vehicle and for a window of a building.
A glass having a possibly high ultraviolet and infrared absorptivity with a high visible light transmittance can be often required for a window of a building.
A glass plate can be employed for a window of a vehicle not only alone but with a variety of coatings applied onto a surface thereof. When the glass has a coating on the surface thereof, the coating reduces the visible light transmittance of the glass plate. Therefore, when the glass has a visible light transmittance having a value that is proximate to a lower limit of the aforementioned permissive range before being applied with a coating, even if the value is in the permissive range (for example, a value of slightly more than 70%), the value of the visible light transmittance easily becomes less than 70% after applying the coating. In this case, the glass can be hardly applied with a desired coating thereon.
The ultraviolet/infrared absorbent glass disclosed in the Japanese Patent H5-78147A has a relatively lighter greenish color shade. The glass having a thickness of 5 mm has a visible light transmittance of 71% at most, which is not sufficiently high. Although the glass has a relatively lighter greenish color shade having an excitation purity of equal to or less than 5%, specifically, the value of the excitation purity is equal to or more than 3.2% and its greenish color shade can not be light enough.
The ultraviolet/infrared absorbent glass disclosed in the Japanese Patent H8-208266A has a relatively high visible light transmittance and includes the total iron oxide expressed as Fe2O3 in a range of 0.52 to 0.63 wt. % and the iron having two valences expressed as Fe2O3 in a range of 28 to 38 wt. % of the total iron oxide. Although the glass provides a high solar rays absorptivity, i.e. a low solar energy transmittance, the visible light transmittance of the glass is in a range of 72.0 to 74.4% when the glass has a thickness of 3.5 mm, in a range of 71.4 to 72.9% when the glass has a thickness of 5 mm, which is not high enough in substantial.
Although the ultraviolet/infrared absorbent glass disclosed in the Japanese Patent H9-208254A has a relatively high see-through visibility and is provided with a high solar rays absorptivity, the visible light transmittance thereof is in a range 65.5 to 67.6% when the glass has a thickness of 5 mm, and it is not high enough in substantial. The excitation purity thereof is equal to or more than 2.9% and the greenish color shade thereof can not be light enough.
An ultraviolet/infrared absorbent glass of a first aspect of the present invention consists of a base glass comprising:
65 to 80 wt. % SiO2;
0 to 5wt. % Al2O3;
0 to 10 wt. % MgO;
5 to 15 wt. % CaO;
10 to 18 wt. % Na2O;
0 to 5 wt. % K2O;
5 to 15 wt. % a total amount of MgO and CaO;
10 to 20 wt. % a total amount of Na2O and K2O;
0.05 to 0.3 wt. % SO3; and
0 to 5 wt. % B2O3,
and a colorant including:
0.35 to 0.55 wt. % total iron oxide (T-Fe2O3) expressed as Fe2O3;
0.08 to 0.15 wt. % FeO;
0.8 to 1.5 wt. % CeO2; and
0 to 0.5 wt. % TiO2,
FeO expressed as Fe2O3 being equal to or more than 20 wt. % and less than 27 wt. % of T-Fe2O3.
An ultraviolet/infrared absorbent glass plate of a second aspect of the present invention is composed of the ultraviolet/infrared absorbent glass of the first aspect wherein the visible light transmittance is equal to or more than 75% when measured by using the CIE illuminant A, the solar energy transmittance is equal to or less than 60%, the ultraviolet transmittance specified by ISO is equal to or less than 15%, the dominant wavelength is between 495 nm and 535 nm when measured by using the CIE illuminant C, and the excitation purity is equal to or less than 2.5% when measured by using the CIE illuminant C.
A colored film-coated ultraviolet/infrared absorbent glass plate of a third aspect of the present invention is provided by applying the colored film having a red color shade with a thickness of between 30 nm and 300 nm which includes the silicon oxide and the fine particles of the gold onto the surface of the ultraviolet/infrared absorbent glass plate of the second aspect.
A window glass of a vehicle of a fourth aspect of the present invention consists of at least two glass plates laminated together with an inner layer of a transparent resin or a spacing layer wherein at least one of these glass plates employs the colored film-coated ultraviolet/infrared absorbent glass plate, the visible light transmittance is equal to or more than 70% when measured by using the CIE illuminant A, the solar energy transmittance is equal to or less than 70%, the ultraviolet transmittance specified by ISO is equal to or less than 15%, and the chromaticity expressed as a, b by using the Lab coordinates is in ranges of xe2x88x922xe2x89xa6axe2x89xa64 and xe2x88x923xe2x89xa6bxe2x89xa63 when measured by using the CIE illuminant C.
The description will be made as regard to an ultraviolet/infrared absorbent glass composition. It should be noted that components will be represented with percentage by weight.
SiO2 is a principal component for forming skeleton of glass. Less than 65% SiO2 lowers durability of the glass and more than 80% SiO2 raises a melting temperature of the glass so high. SiO2 is comprised accordingly within a range of 65 to 80%
Al2O3 is not an essential component but a component for improving the durability of the glass. More than 5% Al2O3 raises the melting temperature of the glass so high. Al2O3 is comprised within a range of 0 to 5%, preferably in a range 0.1% and 2.5%.
CaO improves the durability of the glass and adjusts a devitrification temperature and viscosity of the glass during molding. Less than 5% or more than 15% CaO raises the devitrification temperature of the glass. CaO is comprised accordingly within a range of 5 to 15%.
While MgO may not be comprised essentially, MgO can improve the durability of the glass and adjust the devitrification temperature and viscosity of the glass during molding just as CaO. More than 10% MgO raises the devitrification temperature. The durability of the glass is lowered when the total amount of MgO and CaO is less than 5%, while the devitrification temperature is increased when the total exceeds 15%. MgO is comprised accordingly in a range of 0 to 10% and the total amount of MgO and CaO is in a range of 5 to 15%.
Na2O prompts the glass to melt. The efficiency of promotion of melting becomes poor when Na2O is less than 10%, while the durability of the glass is lowered when Na2O exceeds 18%. Na2O is comprised accordingly in a range of 10 to 18%.
While K2O may not be comprised essentially, K2O can prompt the glass to melt just as Na2O. K2O is preferable not to exceed 5% because of its expensive cost. Therefore, K2O is comprised in a range of 0 to 5%. The efficiency of promotion of melting becomes poor when the total of Na2O and K2O is less than 10%, while the durability of the glass is lowered when the total of Na2O and K2O exceeds 20%. The total amount of Na2O and K2O is in a range of 10 to 20%.
SO3 prompts the glass to be purified. The efficiency of purification becomes poor in the usual dissolution process when SO3 is less than 0.05%, while bubbles formed due to decomposition of SO3 remain in the glass and the bubbles are easily formed during reboiling the glass when SO3 is more than 0.3%. SO3 is comprised accordingly in a range of 0.05 to 0.3%, preferably in a range of 0.05 to 0.15%.
B2O3 is not an essential component but a component for improving the durability of the glass, prompting to melt, and yet enhancing the ultraviolet absorption. The transmittance is reduced also at a visible range, so that the color of the glass is easy to be tinged with yellow and difficulties during molding are caused due to the vaporization of B2O3 when B2O3 exceeds 5%. B2O3 is comprised accordingly in a range of 0 to 5%.
Iron oxide is present in the form of Fe2O3 and the form of FeO in the glass. Fe2O3 is a component for improving the ultraviolet absorptivity coupled with CeO2, TiO2 given later and FeO is a component for improving the heat rays absorptivity.
The desired visible light transmittance and the desired solar rays absorptivity require the total iron oxide (T-Fe2O3) in a range of 0.35 to 0.55%, FeO in a range of 0.08 to 0.15% and the ratio of FeO/T-Fe2O3 (FeO is usually expressed as Fe2O3 when the ratio of FeO/T-Fe2O3 is determined.) of equal to or more than 0.20 and less than 0.27. The solar rays absorptivity cannot be improved sufficiently when the total iron oxide (T-Fe2O3), FeO and the ratio of FeO/T-Fe2O3 are below the lower limit of the respective range, while the visible light transmittance is excessively reduced when these items exceed the upper limit respectively.
It is an object of the present invention to solve the aforementioned conventional problems and to provide an ultraviolet/infared absorbent glass which has a light greenish color shade, particularly an ultraviolet/infared absorbent glass having a light greenish color shade and a high visible transmittance so as to be useful for a window glass of a vehicle and a building.
FeO is especially preferable to be in a range of 0.08 to 0.12%.
Under the aforementioned ranges of the content of the total iron oxide and the ratio of FeO/T-Fe2O3, CeO2 is required to be included in a range of 0.8 to 1.5% to obtain the desired ultraviolet absorptivity. The ultraviolet absorptivity is insufficient when CeO2 is less than 0.8%, while the visible rays having a short wavelength are excessively absorbed so that the visible light transmittance is reduced and the chromaticity expressed as the dominant wavelength becomes higher than the range of 495 nm to 535 nm to emphasize a yellow color of the shade undesirably when CeO2 exceeds 1.5%.
CeO2 is especially preferable to be in a range of equal to or more than 1.0% and less than 1.4%.
Although TiO2 is not an essential component, a small amount of TiO2 may be added suitably in such a range as not to lose the optical properties in the sights of the present invention (i.e. the visible light transmittance of equal to or more than 75%, the dominant wavelength of between 495 nm and 535 nm ) for improving the ultraviolet absorptivity like Fe2O3 and CeO2. Since the glass is easily tinged with yellow when TiO2 is added too much, TiO2 should be in a range of 0 to 0.5%, more preferably not more than 0.15%, most preferably not more than 0.05%.
MnO is not essential but useful for controlling the color tone and the ratio of FeO/T-Fe2O3 coupled with Fe2O3, FeO and CeO2. MnO should be less than 350 ppm since an influence of coloring of MnO itself appears when MnO is added too much.
In the present invention, SnO2 may be added into the glass having the aforementioned proportion in a range 0 to 1% as a reducing agent. While at least one among CoO, Cr2O3, NiO, V2O5, MoO3 and the like may be further added as an ordinary colorant in such a range as not to lose the light greenish color shade in the sights of the present invention, the colorant is not very preferable to be added because it deepens the color tone of the glass and reduces the visible light transmittance.
The glass of the present invention at any thickness in a range of 3.25 mm to 6.25 mm is preferable to have optical properties as followings:
i) A visible light transmittance (Ya) is equal to or more than 75%, preferably equal to or more than 77.5%, when measured by using the CIE illuminant A over the wavelength range of 380 nm to 770 nm.
ii) A dominant wavelength (Dw) is between 495 nm and 535 nm when measured by using the CIE illuminant C over the wavelength range of 380 nm to 770 nm.
iii) A chromaticity of the transmitted light expressed as a, b of the Lab coordinates (Hunter style) when measured by using the CIE illuminant is in ranges of xe2x88x928xe2x89xa6axe2x89xa6xe2x88x923 and xe2x88x921xe2x89xa6bxe2x89xa64, preferably xe2x88x927xe2x89xa6axe2x89xa6xe2x88x925, 1xe2x89xa6bxe2x89xa63.
iv) An ultraviolet transmittance (Tuv) specified by ISO 9050 is equal to or less than 15%.
v) A solar energy transmittance (Tg) is equal to or less than 60%.
vi) An excitation purity (Pe) is equal to or less than 2.5%, preferably equal to or less than 2.0%, when measured by using the CIE illuminant C.
The ultraviolet/infrared absorbent glass plate of the present invention is made up from the ultraviolet/infrared absorbent glass having the aforementioned components and preferable to have a thickness between 3.25 mm and 6.25 mm and optical properties as followings:
1) The visible light transmittance (Ya) is equal to or more than 75%, preferably equal to or more than 77.5%, when measured by using the CIE illuminant A over the wavelength range of 380 nm to 770 nm.
2) The dominant wavelength (Dw) is between 495 nm and 535 nm when measured by using the CIE illuminant C over the wavelength range of 380 nm to 770 nm.
3) The chromaticity of the transmitted light expressed as a, b of the Lab coordinates (Hunter style) when measured by using the CIE illuminant is in ranges of xe2x88x928xe2x89xa6axe2x89xa6xe2x88x923 and xe2x88x921xe2x89xa6bxe2x89xa64, preferably xe2x88x927xe2x89xa6axe2x89xa6xe2x88x925, 1xe2x89xa6bxe2x89xa63
4) An ultraviolet transmittance (Tuv) specified by ISO 9050 is equal to or less than 15%.
5) A solar energy transmittance (Tg) is equal to or less than 60%.
6) An excitation purity (Pe) is equal to or less than 2.5%, preferably equal to or less than 2.0%, when measured by using the CIE illuminant C.
The colored film-coated ultraviolet/infared absorbent glass plate of the present invention is prepared by coating the ultraviolet/infared absorbent glass plate with the colored film or layer having a red color shade with a thickness of between 30 nm and 300 nm which includes the silicon oxide and the fine particles of gold.
Hereinafter, the description will be made as regard to the colored film having a red color shade applied on the surface of the ultraviolet/infared absorbent glass plate.
The colored film or layer having a red color shade is colored by the surface prasmon absorption of the fine particles of gold included therein. The color tone of the film is altered through a shift of the absorption range of the spectral absorbent characteristics depending on an index of refraction of a matrix surronding the fine particles of gold.
The colored film having a red color shade employed in the present invention had a thickness of between 30 nm and 300 nm and includes the fine particles of gold distributed in the matrix composed mainly of the silicon oxide in consideration of durability. The colored film is preferable to include silicon oxide of more than 50 wt. % and not more than 95 wt. %, at least one selected from a group consisting of zirconium oxide, tantalum oxide, aluminum oxide and cerium oxide in a range of 0 to 30 wt. %, fine particles of gold for coloring in a range of 5 to 20 wt. % as the base constituents. The colored film having the red color shade is ordinarily applied onto only one surface on the glass, but it may be applied onto both surfaces of the glass.
Hereinafter, constituents of the colored film will be described.
Silicon oxide is necessary as a matrix material having a small index of refraction to fix the fine gold particles therein and to make the color development of the fine gold particles reddish. Silicon oxide is further necessary to reduce reflectance of the colored film. When silicon oxide is contained too little, the reflectance rises excessively or the colored film becomes more blue tint because the surface prasmon absorption range of the fine gold particles shifts to the long-wave part. When silicon oxide is contained too much, the color of the colored film becomes pale and the efficiency of the silicon oxide becomes poor. Therefore, the content of silicon oxide expressed as SiO2 is more than 50 wt. % and not more than 95 wt. %, preferably between 60 wt. % and 93 wt. %.
The colored film having the red color of the present invention is preferable to include at least one selected from a group consisting of zirconium oxide, tantalum oxide, titanium oxide, aluminum oxide and cerium oxide so as to control the color tone thereof. The reflectance of the film becomes excessively high when these color controlling constituents are contained too much. The color controlling constituents are preferable to be contained in a range of 0 to 30 wt. % in total, more preferably in a range of 0 to 15 wt. % in total.
The fine particles of gold are necessary to make the reddish film with a bright color. When contained too much, the particles grains of gold become to appear on the surface of the film and the durability of the film is reduced. When the fine particles of gold are contained too little, the film is not sufficiently colored. The fine particles of gold are preferable to be contained in a range of 5 to 20 wt. %, particularly in a range of 7 to 17 wt. %.
Too thin film is not sufficiently colored and too thick film reduces the durability thereof to be cracked easily. The film is required to have a thickness between 30 nm and 300 nm, preferably between 50 nm and 250 nm, more preferably between 50 nm and 200 nm.
When the index of refraction of the film is too high, the colored film-coated ultraviolet/infrared absorbent glass plate is increased in reflectance and not preferable in view of appearance. The composition of the film is controlled in such a manner that the film has the index of refraction in a range of 1.4 to 1.70, preferably in a range of 1.40 to 1.60, more preferably in a range of 1.45 to 1.55.
The colored film having a red color shade may be prepared by applying a solution comprising a compound for forming the fine gold particles, a raw material of silicon oxide and optionally raw materials of zirconium oxide, tantalum oxide, titanium oxide, aluminum oxide and cerium oxide, catalysts, additives and an organic solvent and then drying and baking.
Any raw material for silicon oxide is available so far as a transparent film with high strength can be formed in the Sol-Gel route and a superior stability can be secured. Such a raw material for silicon oxide is given next.
Metal alkoxide including tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, a condensate condensed two or more among them (nxe2x89xa72), and a mixture of the condensates is suitable for the raw material of silicone oxide.
Such a condensate may employ hexaethoxydisiloxane (n=2), octoethoxytrisiloxane (n=3), decaetoxytetrasiloxane (n=4), ethoxypolysiloxane (nxe2x89xa75) and the like. Ethylsilicate 40 consisting of a mixture containing monomers (n=1) and condensates (nxe2x89xa72) is preferably employed [the composition is shown on pages 253 through 268 of the document written by J. Cihlar under the title of xe2x80x9cColloids and Surface A: Physicochem. Eng. Aspects 70 (1993)xe2x80x9d, and comprises 12.8 wt. % monomer (n=1), 10.2 wt. % dimer (n=2), 12.0 wt. % trimer (n=3), 7.0 wt. % tetramer(n=4), 56.2 wt. % polymer (nxe2x89xa75) and 1.8 wt. % ethanole].
Alkyltrialkoxysilane is also available wherein a part of alkoxy group of siliconalkoxyde is replaced by alkyl group for example by the linear or branched alkyl group including methyl group, ethyl group, propyl group, butyl group, 2-ethylbutyl group and octyl group, by cykloalkyl group including cyclopentyl group and cyclohexyl group, by alkenyl group including vinyl group, allyl group, xcex3-methacryloxypropyl group and xcex3-achryloxypropyl group, by aryl group including phenyl group, toluyl group and xylyl group, by aralkyl group including benzyl group and phenethyl group, and by xcex3-mercaptopropyl group, xcex3-chloropropyl group or xcex3-aminopropyl group.
The raw material of fine particles of gold may be not only chloride including chloroaurate but sulfide, cyano complex, halogeno complex, thioic acid, thiosulfato acid, sulfito complex, and auric acid of gold, and organogold compound or the like. Among them, chloroauric is preferable because of its stability and ease of acquisition.
Organotitanium compound including titanium alkoxide, titanium acetylacetonate and titanium carboxylate is a preferable raw material of titanium oxide. Titanium isopropoxide or titanium butoxide is employed for titanium alkoxide generally expressed by Ti(OR)4 (R expresses alkyl group having 4 or less carbon atoms) in consideration of the reactivity. It is known that acetylacetonate is also preferable to be used because of its stability when obtaining the titanium oxide. In this case, titanium acetylacetonate is generally expressed by Ti(OR)mLn(m+n=4, nxe2x89xa00, L: acetylacetone). Titanium alkoxide may be varied into titanium acetylacetonate by acetylacetone. A commercial titanium acetylacetonate may be employed. Furthermore, carboxylic acid may be also employed.
Tetramethoxy zirconium, tetraethoxy zirconium, tetraisopropoxy zirconium, tetra-n-propoxy zirconium, tetraisopropoxy zirconium isopropanol complex, tetraisobutoxy zirconium, tetra-n-butoxy zirconium, tetra-sec-butoxy zirconium, tetra-t-butoxy zirconium and the like can be preferably employed as the raw material of zirconium oxide. Alkoxide of zirconium halogenate including zirconium monochloride trialkoxide formed by replacing alkoxy group of the compound expressed in the general formula (4) by halogen group, and zirconium dichloride dialkoxide can be also employed. Zirconium alkoxide formed by chelating the zirconium alkoxide by xcex2-ketoester compound is also available.
Acetoacetic ester expressed by CH3COCH3COOR (R expresses CH3, C2H5, C3H7 or C4H9) including methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate and butyl acetoacetate is given as the aforementioned ketoester compound for the chelating agent. Among them, acetoacetic alkylester, particularly methyl acetoacetate and ethyl acetoacetate are suitable because they are available at relatively low cost. Zirconium alkoxide may be chelated with a part or entire thereof and is preferable to be chelated at (xcex2-ketoester compound)/(zirconium alkoxide) rate of 2 expressed as molar ratio so that the chelate compound is stable. A chelating agent except for xcex2-ketoester compound, for example zirconium alkoxide chelated by acetylacetone is deposited because of its insolubility in solvent including alcoholic and prevents from preparation of the coating solution.
The raw material of zirconium oxide can further employ alkoxyzirconium organic acid formed by replacing organic acid including acetic acid, propionic acid, butanoic acid, acrylic acid, methacrylic acid and stearic acid for at least one of alkoxy groups of the zirconiumalkoxide .
Tantalumalkoxide and tantalum organic compound and the like are suitable for the raw material of tantalum oxide.
Cerium organic compound including ceriumalkoxide, ceriumacetylacetonate and ceriumcarboxylate can be preferably employed for the raw material of cerium oxide. Inorganic cerium compound including nitrate, chloride and sulfate can be also employed, and cerium nitrate and ceriumacetylacetonate are more suitable because of their stability and ease of acquisition.
Aluminum alkoxide, organic aluminum compound and inorganic aluminum compound are suitable for the raw material of aluminum oxide.
Inorganic acid including hydrochloric acid, nitric acid and sulfuric acid or organic acid including acetic acid, oxalic acid, formic acid, propionic acid and p-toluensulfonic acid is employed for a hydrolytic catalyst, when alkoxide is employed for each raw material of silicon oxide, zirconium oxide, tantalum oxide, titanium oxide, aluminum oxide and cerium oxide. The content of these acids may be in a range between 0.01 and 2, preferably in a range between 0.05 and 1.5 at the molar ratio against the metal alkoxide. In hydrolyzing of the metal alkoxide, water is used preferably in a range between 0.01 mol and 10 mol per 1 mol of the metal alkoxide.
As described above, the colored film having a red color shade has major constituents comprising silicon oxide, gold and at least one selected, if necessary, from a group consisting of zirconium oxide, tantalum oxide, titanium oxide, aluminum oxide and cerium oxide for controlling the color of the film. In addition, the film may comprise boron oxide having substantially the same efficiency as silicon oxide, for example, at a rate of 15 wt. % or less. The film may comprise bismuth oxide, zinc oxide, tin oxide, indium oxide, antimony oxide, vanadium oxide, hafnium oxide, chromium oxide, iron oxide, cobalt oxide and the like in a small amount, for example, 15 wt. % or less in total.
The organic coating solution for forming the colored film having a red color shade may be prepared by mixing organic solutions, each of which contains one of the raw materials, at a predetermined proportion.
Types and a mixing proportion of the materials constituting the colored film having a red color shade are preferable to be arranged in consideration of the each compatibility between the employed solvent and the raw compound, the stability of the compound for forming the colored film having a red color shade and the color tone, the resistance of abrasion and the chemical durability of the colored film having a red color shade.
The organic solvent used in forming the colored film having a red color shade is chosen in consideration of the method of applying the compound for forming the colored film having a red color shade. When the colored film having a red color shade is formed in gravure coating, flexographic printing or roll coating, the organic solvent is preferable to have a low evaporation rate because the solvent having a high evaporation rate evaporates before the film is sufficiently cared in the leveling process.
The evaporation rate of the solvent is generally is generally evaluated by the relative index of the evaporation rate in which that of butyl acetate is taken as 100. A solvent having the index of equal to or less than 40 is classified as a solvent having an extremely low evaporation rate and is suitable for an organic solvent used in the gravure coating, the flexographic printing and the roll coating. For example, ethyl cellusolve, butyl cellosolve, cellosolve acetate, diethylene glycol monoethyl ether, hexylene glycol, diethylene glycol, ethylene glycol, tripropylene glycol, diacetone alcohol and tetrahydrofurfuryl alcohol are given.
The coating liquid of the present invention is preferred to include at least one of these solvents, and may include plurals of the solvents for controlling the viscosity and the surface tension of the coating liquid. Further a solvent having a high evaporation rate and over 100 relative evaporation rate including methanol (having the index of relative evaporation rate of 610), ethanol (having the index of relative evaporation rate of 340), n-propanol (having the index of relative evaporation rate of 300) may be added to the solvent having the index of relative evaporation rate of less than 40.
In the present invention, any method of applying the film is available and, for example, spin coating, dip coating, spray coating and printing are given. A printing method including gravure coating method, flexographic printing method, roll coating method and screen printing method is preferable because it can bring a high productivity and apply the compound for forming the colored film having a red color shade efficiently.
In the present invention, the compound for forming the colored film having a red color shade is applied onto the glass base by the applying method mentioned above and then dried at a temperature between 100xc2x0 C. and 400xc2x0 C. for 5 to 200 minutes under an oxidizing atmosphere. After that, the colored film having a red color shade of the present invention having a thickness between 30 nm and 300 nm is formed by baking it at a temperature in a range of 500xc2x0 C. to 700xc2x0 C. or more for 10 seconds to 5 minutes. The fine particles of gold contributing the color developing is formed due to drying and stabilized due to baking.
When the ultraviolet/infrared absorbent glass plate coated with the colored film having a red color shade onto only one surface thereof is employed for a windshield of a vehicle or a window glass of a building, the glass is preferable to be installed in a manner that the surface coated with the colored film having a red color shade thereon is directed to the inside of the vehicle or the building (or that the surface having no colored film thereon is directed to the outside of the vehicle or the building) so as to prevent damages to the colored film having a red color shade. In this case, since an excessively high visible light reflectance of the colored film-coated ultraviolet/infrared absorbent glass plate, particularly on the surface having no colored film, reduces the appearance by dazzling when seen from the outside of the vehicle or the building, the formulation of the colored film is recommended to be selected so that the visible light reflectance of the glass, particularly on the surface having no colored film is equal to or less than 10.0%.
The colored film-coated ultraviolet/infrared absorbent glass plate of the present invention is preferable to have a chromaticity of the transmitted light expressed as a, b in ranges of xe2x88x922xe2x89xa6axe2x89xa64 and xe2x88x923xe2x89xa6bxe2x89xa63, and a lightness expressed as L in a range of 40xe2x89xa6Lxe2x89xa690 by using the Lab coordinates when measured by using the CIE illuminant C, particularly a chromaticity in ranges of xe2x88x922xe2x89xa6axe2x89xa62 and xe2x88x922xe2x89xa6bxe2x89xa62, and a lightness in a range of 50xe2x89xa6Lxe2x89xa690, more particularly a chromaticity in ranges of xe2x88x921.0xe2x89xa6axe2x89xa6xe2x88x921.0 and xe2x88x921.0xe2x89xa6bxe2x89xa61.0, and a lightness in a range of 50xe2x89xa6Lxe2x89xa690, most particularly a chromaticity in ranges of xe2x88x920.5xe2x89xa6axe2x89xa60.5 and xe2x88x920.5xe2x89xa6bxe2x89xa60.5, and a lightness in a range of 50xe2x89xa6Lxe2x89xa690.
The colored film-coated ultraviolet/infrared absorbent glass plate is preferable to have an ultraviolet transmittance (Tuv) specified by ISO 9050 of equal to or less than 15%, particularly equal to or less than 12%, more particularly equal to or less than 10%, and a solar rays transmittance (Tg) of equal to or less than 70%.
Particularly, when the colored film-coated ultraviolet/infrared absorbent glass plate is employed for a window glass of a vehicle, the color of the reflected light from the surface directing to the outside of the vehicle or the reflected light seen from the side of the surface having no colored film of the glass is preferable to have an almost neutral grayish color in view of appearance and the chromaticity of in ranges of xe2x88x924.0xe2x89xa6axe2x89xa64.0, xe2x88x925.0xe2x89xa6bxe2x89xa63.0, particularly in ranges of xe2x88x923.0xe2x89xa6axe2x89xa63.0, xe2x88x923.0xe2x89xa6bxe2x89xa63.0. The visible light reflectance (Rg) of the surface having no colored film thereon and that of the surface coated with the colored film having a red color shade thereon are equal to or less than 10% respectively.
The colored film-coated ultraviolet/infrared absorbent glass plate of the present invention is preferable to have a thickness between 3.25 mm and 6.25 mm, the visible light transmittance of equal to or more than 70%, the solar energy transmittance of equal to or less than 70%, the ultraviolet transmittance of equal to or less than 15% and the chromaticity of the transmitted light in ranges of xe2x88x922xe2x89xa6axe2x89xa64, xe2x88x923xe2x89xa6bxe2x89xa63.
The colored film-coated ultraviolet/infrared absorbent glass plate of the present invention may be formed into the laminated glass due to laminating it to the other glass plate (a colored or non-colored glass plate having no colored film and a glass plate of the same type as the colored film-coated ultraviolet/infrared absorbent glass plate of the present invention are available.) with an inner layer comprising transparent resin materials including polyvinyl butyral and polyester and having a thickness between about 0.2 mm and 2.0 mm preferably in such a manner that the colored film having a red color shade is arranged to be directed inward (or to be faced with an inner layer). The colored film-coated ultraviolet/infrared absorbent glass plate may be also formed into the double glazing unit in a manner that the colored film-coated ultraviolet/infrared absorbent glass plate and the other glass plate are arranged with a spacing (for example between 0.1 and 3 mm) preferably in such a manner that the colored film having a red color shade is arranged to be directed inward and are sealed by hermetic sealing around them to form a laminate having an inner space filled with dry air or gas or having a high vacuum level. The weatherability of the colored film having a red color shade can be improved due to laminating or arranging the glasses in such a manner that the colored film having a red color shade is arranged to be directed inward.
The laminated glass or the double glazing unit in the state of lamination is preferable to have the visible light transmittance (Ya) of equal to or more than 70% when measured by the CIE illuminant A, the solar energy transmittance (Tg) of equal to or less than 70%, the ultraviolet transmittance (Tuv) specified by ISO 9050 of equal to or less than 15% and the chromaticity expressed as a, b by using the Lab coordinates in ranges of xe2x88x922xe2x89xa6axe2x89xa64 and xe2x88x923xe2x89xa6bxe2x89xa63 and is suitable particularly for the window glass of the vehicle. The laminated glass or the double glazing unit is preferable to have a thickness between 1.0 mm and 3.5 mm, particularly between 1.0 mm and 2.5 mm.
A laminated glass prepared due to laminating the colored film-coated ultraviolet/infrared absorbent 2.5 mm thick glass plate having a predetermined dimension and a curved shape and the ultraviolet/infrared absorbent glass plate having no colored film and the same size and shape as the former in one piece via a film of 0.7 mm thick comprising polyvinyl butyral in such a manner that the colored film having a red color shade is faced with the polyvinyl butyral film is given by way of example. The laminated glass plate can be produced from the flat colored film-coated ultraviolet/infrared absorbent glass and ultraviolet/infrared absorbent glass plate in conventional glass bending and laminating process. The laminated glass is particularly suitable for a window glass of a front door of a vehicle (a side window glass being beside the driver""s seat) or front windshield.
Hereinafter, preferable embodiments of the present invention will be described referring to Examples and Comparative Examples.
In the following Example and Comparative Examples, the optical properties of the glass plate are measured as followings:
visible light transmittance (Ya) : JIS R3106 (measuring by using the CIE illuminant A)
dominant wavelength (Dw) : JIS Z8701 (measuring by using the CIE illuminant C)
excitation purity (Pe) : JIS Z8701 (measuring by using the CIE illuminant C)
color tone of the transmitted light (chromaticity a, b, lightness L) : JIS Z 8722, JIS Z8730 (measuring by using the CIE illuminant C)
color tone of the reflected light (chromaticity a, b) : JIS Z 8722, JIS Z8730
ultraviolet transmittance (Tuv) : ISO 9050
solar energy transmittance (Tg) : JIS R3106
visible light reflectance (Rg) : JIS R3106
[I] Hereinafter, some Examples and Comparative Examples of the ultraviolet/infrared absorbent glass and the ultraviolet/infrared absorbent glass plate will be described.